It won't help you with your phone, but isn't there a version of thunderbird on portableapps.com? These install and keep their data on a USB stick, so you can t

It won't help you with your phone, but isn't there a version of thunderbird on portableapps.com? These install and keep their data on a USB stick, so you can take it with you between desktop, laptop, work and friends' computers (no install needed). Edit: might be windows only, though.